An infinitely variable, permanent magnet eddy current and/or hysteresis brake for track-bound vehicles which has already become known (German Patent No. DT-OS 26 38 133) is provided with pole pieces of alternating polarity in longitudinal direction of the track, on which stationary and turnable cylindrical permanent magnets are positioned. Turning the cylindrical permanent magnets by up to 180.degree. causes the magnetic flux and thus the braking force to be switched on or off and thus controlled.
Although a relatively large volume of permanent magnet material can be accommodated between the pole plates and the pole pieces in this type of brake, the induction on the pole faces and pole piece required for an optimal braking force is not achieved.